In a study where two groups are created without random assignment and differ on a skill relevant to the DV, this issue is called?

In a study where two groups are created without random assignment and differ on a skill relevant to the DV, this issue is called?

• A. Non-equivalent groups
• B. Control group
• C. Independent variable levels
• D. Debriefing

Answer: (A)

When participants aren’t randomly assigned to groups, the groups can start off with different characteristics that influence the outcome. This creates non-equivalent groups, a common threat to internal validity because any observed differences might reflect those preexisting differences (like a skill relevant to the dependent variable) rather than the treatment itself. The term specifically captures the problem of groups not being comparable at baseline. A control group is just a comparison group, but without randomization that alone doesn’t guarantee equivalence. Independent variable levels refer to the different conditions of the manipulation, and debriefing is a post-study ethical step. So the issue described is non-equivalent groups.

When participants aren’t randomly assigned to groups, the groups can start off with different characteristics that influence the outcome. This creates non-equivalent groups, a common threat to internal validity because any observed differences might reflect those preexisting differences (like a skill relevant to the dependent variable) rather than the treatment itself. The term specifically captures the problem of groups not being comparable at baseline. A control group is just a comparison group, but without randomization that alone doesn’t guarantee equivalence. Independent variable levels refer to the different conditions of the manipulation, and debriefing is a post-study ethical step. So the issue described is non-equivalent groups.